#include <stdio.h>
#include <stdbool.h>

struct ListNode {
        int val;
         struct ListNode *next;
    };


    bool hasCycle(struct ListNode *head) 
{
 if(head==NULL||head->next==NULL)
 {
    return false;
 }
 struct ListNode *slow=head;
 struct ListNode *fast=head;
 while(fast&&fast->next)
 {
    slow=slow->next;
    fast=fast->next->next;
    if(fast==slow)
    {
        return true;
    }
 }
return false;
}
